Initial import

1 files changed, 666 insertions, 0 deletions

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
new file mode 100644
index 000000000..f2975d4d1
--- /dev/null
+++ b/arch/mips/kernel/process.c
@@ -0,0 +1,666 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
+ * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2004 Thiemo Seufer
+ * Copyright (C) 2013  Imagination Technologies Ltd.
+ */
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/export.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/personality.h>
+#include <linux/sys.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/kallsyms.h>
+#include <linux/random.h>
+#include <linux/prctl.h>
+
+#include <asm/asm.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/dsp.h>
+#include <asm/fpu.h>
+#include <asm/msa.h>
+#include <asm/pgtable.h>
+#include <asm/mipsregs.h>
+#include <asm/processor.h>
+#include <asm/reg.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/elf.h>
+#include <asm/isadep.h>
+#include <asm/inst.h>
+#include <asm/stacktrace.h>
+#include <asm/irq_regs.h>
+
+#ifdef CONFIG_HOTPLUG_CPU
+void arch_cpu_idle_dead(void)
+{
+	/* What the heck is this check doing ? */
+	if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map))
+		play_dead();
+}
+#endif
+
+asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
+
+void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
+{
+	unsigned long status;
+
+	/* New thread loses kernel privileges. */
+	status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
+	status |= KU_USER;
+	regs->cp0_status = status;
+	clear_used_math();
+	clear_fpu_owner();
+	init_dsp();
+	clear_thread_flag(TIF_USEDMSA);
+	clear_thread_flag(TIF_MSA_CTX_LIVE);
+	disable_msa();
+	regs->cp0_epc = pc;
+	regs->regs[29] = sp;
+}
+
+void exit_thread(void)
+{
+}
+
+void flush_thread(void)
+{
+}
+
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
+{
+	/*
+	 * Save any process state which is live in hardware registers to the
+	 * parent context prior to duplication. This prevents the new child
+	 * state becoming stale if the parent is preempted before copy_thread()
+	 * gets a chance to save the parent's live hardware registers to the
+	 * child context.
+	 */
+	preempt_disable();
+
+	if (is_msa_enabled())
+		save_msa(current);
+	else if (is_fpu_owner())
+		_save_fp(current);
+
+	save_dsp(current);
+
+	preempt_enable();
+
+	*dst = *src;
+	return 0;
+}
+
+/*
+ * Copy architecture-specific thread state
+ */
+int copy_thread(unsigned long clone_flags, unsigned long usp,
+	unsigned long kthread_arg, struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	struct pt_regs *childregs, *regs = current_pt_regs();
+	unsigned long childksp;
+	p->set_child_tid = p->clear_child_tid = NULL;
+
+	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
+
+	/* set up new TSS. */
+	childregs = (struct pt_regs *) childksp - 1;
+	/*  Put the stack after the struct pt_regs.  */
+	childksp = (unsigned long) childregs;
+	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* kernel thread */
+		unsigned long status = p->thread.cp0_status;
+		memset(childregs, 0, sizeof(struct pt_regs));
+		ti->addr_limit = KERNEL_DS;
+		p->thread.reg16 = usp; /* fn */
+		p->thread.reg17 = kthread_arg;
+		p->thread.reg29 = childksp;
+		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+		status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
+			 ((status & (ST0_KUC | ST0_IEC)) << 2);
+#else
+		status |= ST0_EXL;
+#endif
+		childregs->cp0_status = status;
+		return 0;
+	}
+
+	/* user thread */
+	*childregs = *regs;
+	childregs->regs[7] = 0; /* Clear error flag */
+	childregs->regs[2] = 0; /* Child gets zero as return value */
+	if (usp)
+		childregs->regs[29] = usp;
+	ti->addr_limit = USER_DS;
+
+	p->thread.reg29 = (unsigned long) childregs;
+	p->thread.reg31 = (unsigned long) ret_from_fork;
+
+	/*
+	 * New tasks lose permission to use the fpu. This accelerates context
+	 * switching for most programs since they don't use the fpu.
+	 */
+	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
+
+	clear_tsk_thread_flag(p, TIF_USEDFPU);
+	clear_tsk_thread_flag(p, TIF_USEDMSA);
+	clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+	clear_tsk_thread_flag(p, TIF_FPUBOUND);
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+	if (clone_flags & CLONE_SETTLS)
+		ti->tp_value = regs->regs[7];
+
+	return 0;
+}
+
+#ifdef CONFIG_CC_STACKPROTECTOR
+#include <linux/stackprotector.h>
+unsigned long __stack_chk_guard __read_mostly;
+EXPORT_SYMBOL(__stack_chk_guard);
+#endif
+
+struct mips_frame_info {
+	void		*func;
+	unsigned long	func_size;
+	int		frame_size;
+	int		pc_offset;
+};
+
+#define J_TARGET(pc,target)	\
+		(((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
+
+static inline int is_ra_save_ins(union mips_instruction *ip)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+	union mips_instruction mmi;
+
+	/*
+	 * swsp ra,offset
+	 * swm16 reglist,offset(sp)
+	 * swm32 reglist,offset(sp)
+	 * sw32 ra,offset(sp)
+	 * jradiussp - NOT SUPPORTED
+	 *
+	 * microMIPS is way more fun...
+	 */
+	if (mm_insn_16bit(ip->halfword[0])) {
+		mmi.word = (ip->halfword[0] << 16);
+		return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
+			mmi.mm16_r5_format.rt == 31) ||
+		       (mmi.mm16_m_format.opcode == mm_pool16c_op &&
+			mmi.mm16_m_format.func == mm_swm16_op);
+	}
+	else {
+		mmi.halfword[0] = ip->halfword[1];
+		mmi.halfword[1] = ip->halfword[0];
+		return (mmi.mm_m_format.opcode == mm_pool32b_op &&
+			mmi.mm_m_format.rd > 9 &&
+			mmi.mm_m_format.base == 29 &&
+			mmi.mm_m_format.func == mm_swm32_func) ||
+		       (mmi.i_format.opcode == mm_sw32_op &&
+			mmi.i_format.rs == 29 &&
+			mmi.i_format.rt == 31);
+	}
+#else
+	/* sw / sd $ra, offset($sp) */
+	return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
+		ip->i_format.rs == 29 &&
+		ip->i_format.rt == 31;
+#endif
+}
+
+static inline int is_jump_ins(union mips_instruction *ip)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+	/*
+	 * jr16,jrc,jalr16,jalr16
+	 * jal
+	 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
+	 * jraddiusp - NOT SUPPORTED
+	 *
+	 * microMIPS is kind of more fun...
+	 */
+	union mips_instruction mmi;
+
+	mmi.word = (ip->halfword[0] << 16);
+
+	if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
+	    (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
+	    ip->j_format.opcode == mm_jal32_op)
+		return 1;
+	if (ip->r_format.opcode != mm_pool32a_op ||
+			ip->r_format.func != mm_pool32axf_op)
+		return 0;
+	return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
+#else
+	if (ip->j_format.opcode == j_op)
+		return 1;
+	if (ip->j_format.opcode == jal_op)
+		return 1;
+	if (ip->r_format.opcode != spec_op)
+		return 0;
+	return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
+#endif
+}
+
+static inline int is_sp_move_ins(union mips_instruction *ip)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+	/*
+	 * addiusp -imm
+	 * addius5 sp,-imm
+	 * addiu32 sp,sp,-imm
+	 * jradiussp - NOT SUPPORTED
+	 *
+	 * microMIPS is not more fun...
+	 */
+	if (mm_insn_16bit(ip->halfword[0])) {
+		union mips_instruction mmi;
+
+		mmi.word = (ip->halfword[0] << 16);
+		return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
+			mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
+		       (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
+			mmi.mm16_r5_format.rt == 29);
+	}
+	return ip->mm_i_format.opcode == mm_addiu32_op &&
+	       ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
+#else
+	/* addiu/daddiu sp,sp,-imm */
+	if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
+		return 0;
+	if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
+		return 1;
+#endif
+	return 0;
+}
+
+static int get_frame_info(struct mips_frame_info *info)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+	union mips_instruction *ip = (void *) (((char *) info->func) - 1);
+#else
+	union mips_instruction *ip = info->func;
+#endif
+	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
+	unsigned i;
+
+	info->pc_offset = -1;
+	info->frame_size = 0;
+
+	if (!ip)
+		goto err;
+
+	if (max_insns == 0)
+		max_insns = 128U;	/* unknown function size */
+	max_insns = min(128U, max_insns);
+
+	for (i = 0; i < max_insns; i++, ip++) {
+
+		if (is_jump_ins(ip))
+			break;
+		if (!info->frame_size) {
+			if (is_sp_move_ins(ip))
+			{
+#ifdef CONFIG_CPU_MICROMIPS
+				if (mm_insn_16bit(ip->halfword[0]))
+				{
+					unsigned short tmp;
+
+					if (ip->halfword[0] & mm_addiusp_func)
+					{
+						tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
+						info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
+					} else {
+						tmp = (ip->halfword[0] >> 1);
+						info->frame_size = -(signed short)(tmp & 0xf);
+					}
+					ip = (void *) &ip->halfword[1];
+					ip--;
+				} else
+#endif
+				info->frame_size = - ip->i_format.simmediate;
+			}
+			continue;
+		}
+		if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
+			info->pc_offset =
+				ip->i_format.simmediate / sizeof(long);
+			break;
+		}
+	}
+	if (info->frame_size && info->pc_offset >= 0) /* nested */
+		return 0;
+	if (info->pc_offset < 0) /* leaf */
+		return 1;
+	/* prologue seems boggus... */
+err:
+	return -1;
+}
+
+static struct mips_frame_info schedule_mfi __read_mostly;
+
+#ifdef CONFIG_KALLSYMS
+static unsigned long get___schedule_addr(void)
+{
+	return kallsyms_lookup_name("__schedule");
+}
+#else
+static unsigned long get___schedule_addr(void)
+{
+	union mips_instruction *ip = (void *)schedule;
+	int max_insns = 8;
+	int i;
+
+	for (i = 0; i < max_insns; i++, ip++) {
+		if (ip->j_format.opcode == j_op)
+			return J_TARGET(ip, ip->j_format.target);
+	}
+	return 0;
+}
+#endif
+
+static int __init frame_info_init(void)
+{
+	unsigned long size = 0;
+#ifdef CONFIG_KALLSYMS
+	unsigned long ofs;
+#endif
+	unsigned long addr;
+
+	addr = get___schedule_addr();
+	if (!addr)
+		addr = (unsigned long)schedule;
+
+#ifdef CONFIG_KALLSYMS
+	kallsyms_lookup_size_offset(addr, &size, &ofs);
+#endif
+	schedule_mfi.func = (void *)addr;
+	schedule_mfi.func_size = size;
+
+	get_frame_info(&schedule_mfi);
+
+	/*
+	 * Without schedule() frame info, result given by
+	 * thread_saved_pc() and get_wchan() are not reliable.
+	 */
+	if (schedule_mfi.pc_offset < 0)
+		printk("Can't analyze schedule() prologue at %p\n", schedule);
+
+	return 0;
+}
+
+arch_initcall(frame_info_init);
+
+/*
+ * Return saved PC of a blocked thread.
+ */
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+	struct thread_struct *t = &tsk->thread;
+
+	/* New born processes are a special case */
+	if (t->reg31 == (unsigned long) ret_from_fork)
+		return t->reg31;
+	if (schedule_mfi.pc_offset < 0)
+		return 0;
+	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
+}
+
+
+#ifdef CONFIG_KALLSYMS
+/* generic stack unwinding function */
+unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
+					      unsigned long *sp,
+					      unsigned long pc,
+					      unsigned long *ra)
+{
+	struct mips_frame_info info;
+	unsigned long size, ofs;
+	int leaf;
+	extern void ret_from_irq(void);
+	extern void ret_from_exception(void);
+
+	if (!stack_page)
+		return 0;
+
+	/*
+	 * If we reached the bottom of interrupt context,
+	 * return saved pc in pt_regs.
+	 */
+	if (pc == (unsigned long)ret_from_irq ||
+	    pc == (unsigned long)ret_from_exception) {
+		struct pt_regs *regs;
+		if (*sp >= stack_page &&
+		    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
+			regs = (struct pt_regs *)*sp;
+			pc = regs->cp0_epc;
+			if (__kernel_text_address(pc)) {
+				*sp = regs->regs[29];
+				*ra = regs->regs[31];
+				return pc;
+			}
+		}
+		return 0;
+	}
+	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
+		return 0;
+	/*
+	 * Return ra if an exception occurred at the first instruction
+	 */
+	if (unlikely(ofs == 0)) {
+		pc = *ra;
+		*ra = 0;
+		return pc;
+	}
+
+	info.func = (void *)(pc - ofs);
+	info.func_size = ofs;	/* analyze from start to ofs */
+	leaf = get_frame_info(&info);
+	if (leaf < 0)
+		return 0;
+
+	if (*sp < stack_page ||
+	    *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
+		return 0;
+
+	if (leaf)
+		/*
+		 * For some extreme cases, get_frame_info() can
+		 * consider wrongly a nested function as a leaf
+		 * one. In that cases avoid to return always the
+		 * same value.
+		 */
+		pc = pc != *ra ? *ra : 0;
+	else
+		pc = ((unsigned long *)(*sp))[info.pc_offset];
+
+	*sp += info.frame_size;
+	*ra = 0;
+	return __kernel_text_address(pc) ? pc : 0;
+}
+EXPORT_SYMBOL(unwind_stack_by_address);
+
+/* used by show_backtrace() */
+unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+			   unsigned long pc, unsigned long *ra)
+{
+	unsigned long stack_page = (unsigned long)task_stack_page(task);
+	return unwind_stack_by_address(stack_page, sp, pc, ra);
+}
+#endif
+
+/*
+ * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
+ */
+unsigned long get_wchan(struct task_struct *task)
+{
+	unsigned long pc = 0;
+#ifdef CONFIG_KALLSYMS
+	unsigned long sp;
+	unsigned long ra = 0;
+#endif
+
+	if (!task || task == current || task->state == TASK_RUNNING)
+		goto out;
+	if (!task_stack_page(task))
+		goto out;
+
+	pc = thread_saved_pc(task);
+
+#ifdef CONFIG_KALLSYMS
+	sp = task->thread.reg29 + schedule_mfi.frame_size;
+
+	while (in_sched_functions(pc))
+		pc = unwind_stack(task, &sp, pc, &ra);
+#endif
+
+out:
+	return pc;
+}
+
+/*
+ * Don't forget that the stack pointer must be aligned on a 8 bytes
+ * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
+ */
+unsigned long arch_align_stack(unsigned long sp)
+{
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		sp -= get_random_int() & ~PAGE_MASK;
+
+	return sp & ALMASK;
+}
+
+static void arch_dump_stack(void *info)
+{
+	struct pt_regs *regs;
+
+	regs = get_irq_regs();
+
+	if (regs)
+		show_regs(regs);
+
+	dump_stack();
+}
+
+void arch_trigger_all_cpu_backtrace(bool include_self)
+{
+	smp_call_function(arch_dump_stack, NULL, 1);
+}
+
+int mips_get_process_fp_mode(struct task_struct *task)
+{
+	int value = 0;
+
+	if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
+		value |= PR_FP_MODE_FR;
+	if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
+		value |= PR_FP_MODE_FRE;
+
+	return value;
+}
+
+int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
+{
+	const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
+	unsigned long switch_count;
+	struct task_struct *t;
+
+	/* Check the value is valid */
+	if (value & ~known_bits)
+		return -EOPNOTSUPP;
+
+	/* Avoid inadvertently triggering emulation */
+	if ((value & PR_FP_MODE_FR) && cpu_has_fpu &&
+	    !(current_cpu_data.fpu_id & MIPS_FPIR_F64))
+		return -EOPNOTSUPP;
+	if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre)
+		return -EOPNOTSUPP;
+
+	/* FR = 0 not supported in MIPS R6 */
+	if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
+		return -EOPNOTSUPP;
+
+	/* Save FP & vector context, then disable FPU & MSA */
+	if (task->signal == current->signal)
+		lose_fpu(1);
+
+	/* Prevent any threads from obtaining live FP context */
+	atomic_set(&task->mm->context.fp_mode_switching, 1);
+	smp_mb__after_atomic();
+
+	/*
+	 * If there are multiple online CPUs then wait until all threads whose
+	 * FP mode is about to change have been context switched. This approach
+	 * allows us to only worry about whether an FP mode switch is in
+	 * progress when FP is first used in a tasks time slice. Pretty much all
+	 * of the mode switch overhead can thus be confined to cases where mode
+	 * switches are actually occuring. That is, to here. However for the
+	 * thread performing the mode switch it may take a while...
+	 */
+	if (num_online_cpus() > 1) {
+		spin_lock_irq(&task->sighand->siglock);
+
+		for_each_thread(task, t) {
+			if (t == current)
+				continue;
+
+			switch_count = t->nvcsw + t->nivcsw;
+
+			do {
+				spin_unlock_irq(&task->sighand->siglock);
+				cond_resched();
+				spin_lock_irq(&task->sighand->siglock);
+			} while ((t->nvcsw + t->nivcsw) == switch_count);
+		}
+
+		spin_unlock_irq(&task->sighand->siglock);
+	}
+
+	/*
+	 * There are now no threads of the process with live FP context, so it
+	 * is safe to proceed with the FP mode switch.
+	 */
+	for_each_thread(task, t) {
+		/* Update desired FP register width */
+		if (value & PR_FP_MODE_FR) {
+			clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
+		} else {
+			set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
+			clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
+		}
+
+		/* Update desired FP single layout */
+		if (value & PR_FP_MODE_FRE)
+			set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
+		else
+			clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
+	}
+
+	/* Allow threads to use FP again */
+	atomic_set(&task->mm->context.fp_mode_switching, 0);
+
+	return 0;
+}